The present invention relates generally to methods and apparatuses for provisioning communications channels in telecommunication or computer networks, and more particularly to a method and apparatus for provisioning communications channels in a telecommunications or computer network that operates optically.
Communications networks, including optical communications networks, generally comprise many nodes at which the data stream is coupled from one incoming port to an outgoing port to route the data stream to the desired destination. An example of an optical node is an optical cross-connect or optical add-drop multiplexer.
In an optical network, in addition to the payload channels, each network node is sometimes connected to its adjacent or neighboring nodes and a master node by a control channel. Each network node may have many incoming and outgoing ports, e.g., 4, 8, 16, 64, etc. Each port is connected to a port on a neighboring node. Multiple ports one on node may be connected to the same node on their terminal side. However, each port on a node is terminated in only one other port.
When provisioning connections in any network, including optical networks, it is necessary to identify the port interconnections between adjacent nodes (e.g., ONNs) before attempting to setup channel connections, such as optical channel connections in an optical network cross-connect. Manually identifying the node interconnections and populating a port adjacency table in each node is possible, but cumbersome, even if the table is subsequently dynamically updated as and when connections are made and released. This is particularly problematic when the numbers of ports per node are large. Moreover, as data networks are ever increasing in size, manual techniques for identifying the ports will become increasingly tedious.
Currently, an automatic method for port interconnection discovery in all-optical cross-connect-based network does not exist. Although such a scheme may be feasible in an optical-electrical cross-connect-based network, in which optical-electrical-optical conversion takes place in each optical network node (ONN), techniques for automated port interconnection discovery are limited due to the lack of optical to electrical conversion in an all-optical cross-connect. Moreover, in an optical communication network, some nodes are not capable of generating an information-bearing signal that can be transmitted over one of the optical communications payload channels. This is because the node lacks the ability to convert a signal from the electrical domain to the optical domain. It is the precise ability of the node to operate completely optically that allows the node to operate at extremely high speeds. Consequently, requiring an electrical conversion in the process would unduly limit the operating speed or increase the cost. As a result, techniques for automatically provisioning nodes in an optical/electrical communications network are not possible in all-optical communications networks.
The present invention is therefore directed to the problem of developing a method and apparatus for automated port interconnection discovery in an optical network employing optical cross-connects that operate completely optically (i.e., all-optical).